Ex 12.1, 1 There are 20 girls and 15 boys in a class. (a) What is the ratio of number of girls to the number of boys?
Number of girls = 20
Number of boys = 15
Ratio = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑔𝑖𝑟𝑙𝑠)/(𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑏𝑜𝑦𝑠)
= 20/15
= 4/3
∴ Required ratio is 4 : 3
Ex 12.1, 1 There are 20 girls and 15 boys in a class. (b) What is the ratio of number of girls to the total number of students in the class?Total number of students = Number of girls + Number of boys
= 20 + 15
= 35
∴ Ratio = (𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑔𝑖𝑟𝑙𝑠)/(𝑇𝑜𝑡𝑎𝑙 𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑠𝑡𝑢𝑑𝑒𝑛𝑡𝑠)
= 20/35
= 4/7
∴ Required ratio is 4 : 7